The present invention relates to a sub-miniature switch of a type which is known in the state of the art, in particular from EP 618 603 B1 and GB 2 142 471 A.
The sub-miniature switches according to the prior art have a housing with a cover, an actuator protruding from the housing, and external terminals. The actuator is offset from the center of the housing. The terminals are connected in an electrically conducting way with fixed contacts positioned inside the housing. A moveably supported, in particular rotatably supported, contact maker can take up two positions depending on the position of the actuator. In both the first and second switching positions, the contact maker is held by a bistable spring arrangement (tension spring).
An additional component, a hold-down plate or separator or auxiliary actuator is provided in the housing, which is pushed through by the actuator as it is switched over from the first switching position to the second switching position. In the prior art, the auxiliary actuator is supported at the actuator.
Such sub-miniature switches are used in the industrial field in tube motors of roller blind drives or roller sun visor drives in order to sense the end-of-travel positions of the roller blind or sun visor. Stringent requirements are put on these micro-switches with respect to their operating safety and service life. The capacitive loads on the contacts in the end-of-travel positions easily lead to sticking or fusing of the contacts. The normal contact release force exerted by the tension spring of the bistable spring arrangement no longer suffices to pull away the stuck contact. This can lead to the destruction of the drive as it is not switched off. In order to avoid this it has to be ensured that the contact to be opened is mechanically opened after a defined travel distance of the actuator despite sticking of the contacts.
For this purpose, additional separators are known. Due to the addition of a component, the manufacture and assembly of these micro-switches is made more complex.
It is an object of the present invention to provide a sub-miniature switch of the type initially mentioned with a structurally simple and reliable forced-opening capability without increasing the structural size.